Powertrain, shared range

P3459 Cylinder 8 Deactivation/Intake Valve Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

When the ground-side control line of the cylinder 8 deactivation solenoid touches ground, the ECM stores P3459. GM publishes this test for the 2019 L84 V8 with Dynamic Fuel Management: driver off, impedance below 0.5 ohm to ground, a minimum of 11 V on the relay feed and 425 rpm, 20 errors in 25 samples, Type B. Some GM controllers log P3457 at the same time. Because a DFM engine may skip any cylinder, a fault on cylinder 8 shuts down a system that otherwise uses this cylinder routinely; GM's LTA and LT2 also include cylinder 8 in their fixed deactivation set. A ground short on the solenoid's high-side feed has its own GM code, P311A. P3460 is the short to power.

Likely causes

Cylinder 8 control wire grounded through damaged insulation
Internal short in the cylinder 8 solenoid
Contamination in the solenoid connector
Output driver in the engine control module damaged

Symptoms

  • Check engine lamp on after the second trip
  • Engine runs on all eight cylinders at all times
  • Higher fuel consumption

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–900
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

cylinder deactivation solenoidwiring harnessecm

Related codes

P3457P3458P3460P3463P3497

References: law.cornell.edu, gsi.ext.gm.com, static.nhtsa.gov.